U.S. Pat. No. 4,717,949 (Eichenlaub) discloses autostereoscopic displays that employ a flat screen on which are displayed a plurality of thin, vertical light emitting lines. An image forming device, such as a liquid crystal display, including rows and columns of pixels is located in front of the screen and forms images by varying the transparency of the individual pixels arranged across its surface. The screen and light valve are arranged so that an observer sees the light emitting lines through one set of pixels with the left eye and the same lines through a different set of pixels with the right eye.
This invention provides an autostereoscopic display device. Generally, the device comprises an image forming device comprising display pixels arranged in rows and columns; a first substrate comprising alternating strips, the alternating strips comprising strips having a first optical property which are separated by strips having a different, second optical property; and a polarizing substrate, where each of the first substrate and the polarizing substrate is independently optically disposed in front or behind the image forming device.
According to various preferred embodiments, the device includes a first polarizing substrate optically disposed in front or behind the image forming device and having alternating strips of polarization film separated by clear, nonpolarizing strips, and a second polarizing substrate optically disposed in front or behind the image forming device. According to other preferred embodiments, the device includes a light retardation substrate that includes first alternating strips that retard a component of linearly polarized light therethrough by one-half wavelength, said first strips separated by second alternating strips that retard a component of linearly polarized light therethrough by one wavelength. For these embodiments, the alternating strips are preferably arranged vertically. The image forming device may be a transmissive, electronically addressed liquid crystal display, including a liquid crystal layer addressable in an array of individual pixel elements, and the device further comprises a backlight source. Alternately, the image forming device may be an emissive, addressable display with display pixels arranged in rows and columns.
For the embodiments employing the polarizing substrate with alternating strips of polarization film, the device may include a secondary, non-image forming LCD having no pixel structure, where the LC panel is switchable between autostereoscopic image and 2D viewing by application and removal of the voltage to the liquid crystal layer in the secondary LCD.
According to various embodiments, a movable, second polarizing substrate may be removably placed in front of the substrate containing the alternating strips. When the movable polarizing substrate is placed in front of the strips in a certain orientation, autostereoscopic imaging is viewed by the observer, and when this polarizing substrate is removed, 2D imaging is viewed.